1. Field of the Invention
This invention relates to the field of surgical instruments for retrieving internal body tissue and, more particularly, to a surgical instrument used in endoscopic surgery for retrieving internal body tissue with an endoscopic pouch.
2. Background of the Invention
Tissue retrieval devices have been developed for use in endoscopic surgery to remove tissue from a patient's body. Typically these devices comprise a specimen-collecting pouch placed at the distal end of a pusher rod. The pusher rod is inserted into the patient's body via a tiny insertion and the pouch is deployed once it is near the surgical site. Gaining close proximity to the tissue to be removed, placing the tissue in the pouch, closing the pouch, and removing the now-filled pouch from the body are the main steps to be performed with the device.
Pouches used with tissue retrieval devices often employ a means for closing the pouch to prevent spillage of tissue or fluids into the patient's body. Typical closure means include a drawstring or a wire loop.
In many state of the art devices, the mouth of the pouch does not allow for easy collection of the sample and/or removal of the pouch from the patient's body. This is because of problems associated with the slipknot often used to initially close the pouch. For example, in some prior art devices, once the pouch is closed it cannot be reopened until the pouch is removed from the patient.
A surgical retrieval device with a drawstring for closing the pouch is disclosed by Clayman et al., U.S. Pat. No. 5,037,379. The drawstring is used to close the bag closed and pull the bag from the body cavity through a tube.
Kindberg et al., U.S. Pat. No. 5,143,082, discloses a surgical device for enclosing a body organ or tissue and which includes a strand extending through a tube and formed into a noose about the open end of a surgical bag.
Wetter et al., U.S. Pat. No. 5,190,555, discloses another endoscopic tissue retrieval device that includes a drawstring used for closing and opening a funnel-shaped bag.
U.S. Pat. Nos. 5,465,731 and 5,647,372 disclose yet another endoscopic tissue retrieval comprising a pouch supported by a closed metal loop. The bag is ripped away from the metal loop during the drawstring closure along a perforated line circumscribing the mouth of the pouch.
The aforementioned patents and device are not admitted to be prior art by their mention in this Background section.
Many state-of-the-art pouches fail during their removal from the patient. This is because a great deal of force is applied to a filled bag as a surgeon attempts to pull it through the typically tiny laparoscopic surgical incision made in the skin and muscle layers of the patient.
Separately, bags often come into contact with sharp surgical instruments and rip as a result.
A need exists in the art for a reliable tissue retrieval device comprising a sturdy bag with a large mouth that is securely attached to its support but that can be released from the support without having to close the mouth of the bag. Such a device should also allow full access to the retrieval pouch prior to insertion into the patient so as afford in situ pre-treatment of the bag. Furthermore, the device should provide a means for preventing accidental deployment or closure of the pouch as well as accidental removal of the pouch from its support during collection of tissue. The device should also provide a means to scrape tissue from adjacent adhering structures for more efficient tissue extraction from the body.